Motor fuel and its production



July 19, 1932. L. M. HENDERSON ET AL 1,868,102

MOTOR FUEL AND ITS PRODUCTION Filed D eo. 24. 1928 Patented July 19, 1932 UNITED STATES `PATENTl OFFICE LAWRENCE M. HENDERSON, OF NARBERTH, ANI) SEYMOUR W. FERRIS, OF. LAN SDO'WNE,

`PENNSYLVANIA, ASSIGNORS TO THE ATLANTIC REFINING GOMPAN Y, .OF PHILA- DELPHIA, PENNSYLVANIA., A CORPORATION OF PENNSYLVANIA f MOTOR FUEL AND ITS PRODUCTION Application lfiled December 24, 1928. Serial No. 328,286.

uOur invention relates to a motor fuel of relatively high antidetonating properties and aprocess for producing it.

In accordance with our linvention crude petroleum or a product thereof is subjected to highly eflicient fractionation whereby there are separated fractions of narrow range-s of boiling points within the boiling range of gasoline, some of which have a lower content of paraiiine hydrocarbons than the gasoline obtained by the usual distillation ofa similar petroleum product while other fractions have a higher content of parafiine hydrocarbons.

Petroleum is a mixture of various series of hydrocarbons containing within each series individual hydrocarbons of different boiling points. The relative percentages of the different series vary in different crudes; for example, the so-called paraliine base crudes, as those from Pennsylvania, have a high percentage of compounds of the parafline series, while the naphthene base crudes of the Gulf Coast have a relatively high percentage of members of the naphthene series and correspondingly lower percentage of paratlines.

There are certain characteristic relationships between the properties'of the hydrocarbons of the various series; for example, for a given boiling point the paratlines have the lowest specific gravity, the olenes, naphthenes and aromatics having specific gravities increasing in the order named. Similarly the aniline point, i. e., the critical temperature of solution of aniline in the hydrocarbons, is relatively high for the paraines as compared to the other series. By comparison of these roperties an approximation of the nature o a petroleum fraction may be ob` tained. Y

lThe tendency of a gasoline to detonate when used in an internal combustion engine is dependent to a large extent upon the relative percentages of the various series of hydrocarbons present. For the same boiling range the strai ht chain paraflines detonate most readily, t e olelines next, followed by the naphthenes and aromatics. From the standpoint of antiknock value, thosegasolines relatively low in content of the straightchain paratline hydrocarbons and relativelyA high in olefines, naphthenes and particularly aromatics are most desirable.v For this reason California gasoline having a high naphthene content is more effective as an antidetonating` fuel than gasoline from Pennsylvania crude. l

' Gasoline as produced by straight-rundistillation, or ,by cracking or conversion of higher into lower boiling oils, is a mixture of the lower boiling hydrocarbons of the' various series. When such liquid is distilled without close fractionation of the vapors,

' i. e., with no special provision forbringing reflux liquid into heat interchange relation therewith, and a series of cuts of increasing boiling points is collected, a relatively smooth curve is obtained if the specific gravity of the individual cuts be plotted against the 50% boiling point of the respective cuts. The

lgeneral lformof such "a curve for atypical gasoline i shown in Curve A,|Fig. 1. Practically all gasolines give a curve of substantially this shape although the location of the curves may vary somewhat according to 'the source, for example, the curve for Pennsylvania gasoline of low specific gravity for a given volatility will lie below the curve for a Gulf Coast gasoline of higher specific gravity of the same volatility. v

When,`howe`ver, a gasoline is subjected to eicien't fractional distillation', as by brin ing it into heat interchange relation wi h suitably controlled quantities of reiiux liquid resenting high specificgravity cut'sand the troughs low specific gravity cuts which, as

indicated by the relationship .between the ywo ' 50% boiling -point and specific gravityare of low and high parafline hydrocarbon content respectively. The relative paralline content of these fractions is further shown by,l

,'5 reference to the Curve C of Fig. 2, in which v the aniline point, i; e., the critical temperature of*v solution of aniline, is plotted against peaks in the Curve C, the peaks indicatinglow aniline point. The peaks in both curves .15 are indications of low parafline lcontent as compared with the low specific gravity and high aniline points of the troughs.

these fractions of low paralline hydrocarbon content by subjecting gasoline or petroleum e or petroleum fractions containing gasolinelike constituents to highly elicient fractional distillation andto blend the low paraifine content fractions -thus obtained to produce 5 amotor fuel-of highantidetonating properties. In some instances, it may be desirable to add to the blend thus obtained other petroleum fractions of suitable boiling range, as within the boiling range of-gasoline.

Detonationis dependent not lonly upon the chemical composition of the hydrocarbons present in the fuel, but also upon the volatility of these hydrocarbons, those of lower boihng point having less tendency to detonate than the higher boiling hydrocarbons.

- v As a consequence, the lower boiling portion of the gasoline, for example that'portion boiling below 80 degrees C., is of suitable antiknock' properties and in general,

o need not be subjected to the efficient fractionation. l

For example, in accordance with 'one' method of practicing our invention the gasoline or oil containing gasoline-like components may be -continuously efficiently fractionally distilled in a system, comprising the well-known pipe still and fractionating column, in which the oil is heated in the Ipipe still to a temperature sufl'icient tovaporize the desired components and is then introduced into a fractionating column in which the rising vapors are brought into intimate heat interchange contact with descending reflux liquid thereby effecting aseparation of the vapors into liquid fractions, of varying antiknock properties, taken off as sidestreams from the column. Those corre-- spending with one or more peaks of Curves A50 lB or C are the fractions selected for blending because of their high antidetonating characteristics. The low boiling portion' of the vapors, of good antidetonating properties,v

t is the ob] ect of our invention to separateA from any sourceA containingl gasoline-likev components, including craeked'gasoline and crude petroleum, and anyy method of fractional distillation may be utilized which makes a sharp separation of the components within the gasoline boiling range into cuts of narrow range of boiling points and of relatively high and relatively low parafine content respectively, so that, when the latter are blendedtogether with or'withou/tthe addition of other hydrocarbon fractions lying Within the gasoline boiling range amotor fuel of relatively high antiknock properties is produced.

Fractional distillation of petroleum to` produce gasoline and otherfractions is well known 1n the art and that, per se, we do not claim as our invention. In such processes the gasoline is obtained, in general, as one fraction, the antidetonating profperties `of which are dependent primarily upon itssource and the content of high boiling components. What we claim is the separation of such gasoline or suitable oil by fractional distillation into fractions of narrow range of boiling points and of progressively increasing boiling point, but of irregular antidetonating qualities, and blending the selected fractions of high antidetonating qualities to produce an improved motor fuel.

We prefer so to control the fractionation that each of the individual fractions obtained shall have a total boiling range of about 5 degrees C. and not more than 10 degrees C. when determined by the A. S. T. M. Distillation test No. D 86-27 modified in that the dry point is determined by noting the temperature at Awhich the last drop of liquid disappears from the flask rather than the maximum 'temperature reached by the thermometer on continued heating of the flask as specified in the A. S. T. M. method.

For the fractionating system hereinbefore.

referred to there may be employed one generally, though not necessarily specifically, of the character disclosed in U. S. Patent No. 1,680,421. It shall be understood however, that there may be employed any suit.- able method of fractionation having the eficiency or yielding the sharpness of cuts or fractions of the character hereinbefore described.

The charging stock or starting material is any suitable hydrocarbon oil. It may be crude petroleum or a product thereof. It may be a cut whose components have boiling points extending over a considerable range; more particularly and preferably it is a gasoline. The fractions of irregularly varying antidetonating qualities, from among which are selected those having relatively high an- 'tidetonating qualities, have boiling points lying within the gasoline boiling point range. The selected fractions are blended wi th each other and one of the fractionsmay comprise the lowest boiling components of the oil which is fractionated or a part thereof; or the selected fractions may be blended with any other suitable oil.

The fractions of high antidetonating quality selected for blending purposes, are those of relatively narrow range of boiling points substantially corresponding, respectively, with the peaks of the -Curves B or C. With these select-cd fractions there alternate, in a sense, other fractions of low or lower antidetonatingqualities corresponding substantially with the troughs or cusps of the Curves B or C, and these latter-fractions are not utilized. v

Our improved product is characterized by the fact that, first, it comprises a-blend of fractions of relatively high antidetonating qualities, selected from a series of fractions, including the first-named fractions and others having antidetonating qualities which are low or lower than'those of the selected fractions; and, second,comprises a blend if such selected fractionswith another fraction or fractions, preferably of substantial or high antidetonating quality, of .a boiling range beyond or outside the boiling range of the selected Vlfractions, and generally or preferably of a boiling point or range lower than that`of the selected fractions.

1. The process of obtaining gasoline: of high antidetonating quality, which comprises separating hydrocarbon oil containing gasoline-like components by subjecting said oil to fractional distillation into a series of fractions of irregularly varying antidetonating qualities, and combining those fractions of relatively high antidetonating quality.

2. The process of improving the antidetonating value of hydrocarbon 4motor fuel, which comprises separating said motor fuel by subjecting it to fractional distillation into a series of fractions of irregularly varying antideton ating qualities, and combining those fractions having higher antidetonating quality than that of the original mot-or fuel.

3. The process of distilling hydrocarbon oils containing gasoline-like components, which comprises vaporizing at least a portion of the-oil, separating by fractional distlllation the vapors of the higher boiling portion of the gasoline-like components into a series of fractions of progressively increas- -ing boiling points and irregularly varying antidetonating qualities, condensing the lower boiling portion'of the gasoline-like components to form a single fraction, and blending those fractions of relatively'l high antidetonating qualities with the lower boiling portion of the gasoline-like components. y

er boiling portion, and blending therewith said one or more sidcstream fractions of relatively high antidetonating qualities.

5. The process of obtaining gasoline of high anti-detonating quality which comprises separating"hydrocarbon oil containing gasoline-like components, by subjecting it to fractional distillation, into a series of fractions of progressively increasing boiling peint some of which are more paraiinic and others less paralfinic than the original gasoline-like components, selecting those fractions so produced within the gasoline boilingrange whose paraiinnhydrocarbon content is relatively low and blending them to form a product whose content of paraflin hydrocarbons is less than that of the original gasoline-like components. l

6. The process of distilling hydrocarbon oils containing gasoline-like components, which comprises vaporizingI at least a portion of the oil, condensing the vapors of that portion of the gasoline-like components boiling below 80 degrees C. to form a single fraction, separatingby fractional distillation the detonating quality of a hydrocarbon motor fuel which comprises separating said motor fuel by fractional distillation into a `series of fractions of progressively increasing 50% boiling points and of suiiiciently close boiling range that when their specific gravities are plotted against their 50% boiling points a curve is obtained which shows a succession of peaks and troughs, the peak fractions be-- ing less paraiinic and 'more `highly antidetonating than the trough fractions, and

' combining peak fractions to produce a motor fuel substantially more highly anti-detonating than the original motor fuel.

8. The process of improving the antidetonating quality of a hydrocarbon motor fuel.u'l1ich comprises separating it by fractional distillation into a series of fractions of progressively increasing 50% boiling points and of sufficiently close boiling range that' when their aniline points are plotted inversely against their 50% boiling points a curve is obtained which shows a succession of peaks and troughs, the peak fractions being less paraffinic and more highly anti-detonating than the trough fractions, and combining then fractionally distilling the remainder of the motor fuel first mentioned to separate therefrom those fractions which the determination aforesaid indicates will produce the desired motor fuel, and blending them. LAWRENCE M. HENDERSON. SEYMOUR W. FERRIS.

peak fractions to produce a motor fuel sub-v,

stantially more highly anti-detonating than the original motor fuel.

9.l The process of producing a motor` fuel of improved anti-detonating quality which comprises subjecting a hydrocarbon oil containing gasoline-like components to fractional distillation to separate said gasolinelike components ihto a series of fractions of progressively increasing boiling points and of individual boiling range not greater than 10 degrees C. so that when their specific gressively increasing 50% boiling points and y of individual boiling rangeinot greater than 5 degrees C. so that when. their specific gravities are plotted against the 50% boiling Apoints a curve is obtained which shows a succession of peaks and troughs, the peak fractions being less parailinic and more antidetonating than the vtrough fractions, and combining peak fractions to produce a motor fuel substantially more highly anti-detonating than the original gasoline-like'components.

11. The process of obtaining a motor fuel i of high anti-detonating quality from one of lower anti-detonating quality which comprises rst submitting a portion of the fuel of lower anti-detonating quality to close fractionation to obtain a series of closely cut fractions and determining which of the fractions so obtained when combined produce a motor fuel of higher anti-detonating quality, 

